This invention relates generally to an oil mist generating system, and more particularly concerns an oil mist generating system and method for system start-up and monitoring.
Centralized mist generating systems are used to provide an oil mist for continuous lubrication of multiple pieces of machinery. Oil mist generating systems generally include a pressurized inlet gas supply, an inlet oil supply feeding into an oil reservoir, a mist generating head on the reservoir, and instrumentation for monitoring and controlling the operating conditions of the system. Using the energy of pressurized gas, oil is atomized into very fine particles at the mist generating head. The oil mist is conveyed long distances in the gas stream and directed to machinery parts for lubrication. Oil mist lubrication is used to lubricate all kinds of machine elements ranging from tiny, ultra-high speed parts of dental drills to huge chains, cams, gears, bearings and other moving machine parts.
In the past, oil mist generating systems were provided with minimal instrumentation for monitoring and control. More recently, attempts have been made to upgrade the monitoring and control of such systems. Built-in, solid-state programmable control units for oil mist generating systems are now available. However, monitoring and control of oil mist generating systems remains a concern among users and an area where needs still exist. Even when solid-state monitoring and control are available there is still a need to enhance the overall user-friendliness of the system. Problems particularly persist in the area of system start-up, troubleshooting (finding and correcting faults), and changeover to stand-by systems when necessary and available.
Monitoring and control of oil mist generating systems during start-up has been inadequate to date. When an oil mist generating system is initially turned on, the air and oil are cold and will not produce mist for lubricating machinery. Of course, mist must be available when the machinery is turned on or the equipment may be damaged. Unforeseen situations may also arise during start-up which place the user and system at risk, particularly since the oil is heated and under pressure. Moreover, many oil mist generating systems are located in hazardous areas which enhances the dangerous circumstances. Unfortunately, users presently start conventional oil mist generating systems with little meaningful input from the system instrumentation. Conventional solid-state monitoring and control systems are not capable of guiding the user through a start-up sequence for the system. Typically, the system operating manual serves as a guide for start-up, but more often the user relies on general system experience.
Once the oil mist generating system is running, routine maintenance accompanied by monitoring for system faults are ordinarily all that is needed. Minor adjustments are ordinarily not necessary. However, when faults occur, conventional oil mist generating systems lack an automated approach for dealing with the problem. Usually, only a general fault condition is indicated leaving to the user the task of diagnosing and correcting the problem. Again, the only useful reference source is the operating manual or the user's own experience. Even after the reason for the fault condition is identified, the user must still decide how to address the problem. Present systems do not offer the user such guidance outside of the operating manual. Moreover, since oil mist generating systems are used in industrial settings, such as refineries and textile factories, downtime can be extremely costly, particularly if the fault is not diagnosed quickly. Failure of the system may result in the destruction of high cost equipment. Thus, efficient troubleshooting is important.
Stand-by units are an added option in an overall oil mist lubrication system. When a regular oil mist generating unit is out of ser vice due to a malfunction or maintenance, the user temporarily switches operation to the stand-by unit. This is accomplished by using multiple two-way valves to turn off the air and oil sources of the regular unit and close the mist outlet, and then turning on the corresponding two-way valves of the reserve unit. Unfortunately, piping for the combined regular and stand-by system configuration is complicated. Also, the opportunity for error is significant, especially if the valves are not closed or opened in the proper sequence.
For the foregoing reasons, there is a need for improved monitoring and control of the operation of oil mist generating systems. An automated start-up sequence for oil mist lubrication generating systems is needed which, at a minimum, ensures that start-up proceeds properly and that mist is available before the machinery to be lubricated is turned on. The automated start-up should ideally provide guidance for the user contributing to the safety of the user, the system, and the machinery. There is also a need for improved troubleshooting of oil mist generating systems. Means are needed to quickly identify oil mist generating system malfunctions and speed diagnosis and correction. When temporary switching to a reserve unit is necessary, there is a need to simplify the configuration and piping and thus lessen the opportunity for error that might cause improper changeover and possible damage to the lubricated machinery.